1. Field of the Invention
The present invention relates to a motor drive apparatus and an electronic apparatus.
2. Description of the Related Art
A stepping motor is advantageous to a miniaturization. In order to prevent stepping out, it is known to attach a position detector configured to detect a rotational position of a rotor to the stepping motor and to provide a feedback control that switches an electrification state to a coil in accordance with its output. Japanese Patent Laid-Open No. (“JP”) 10-150798.
Other prior art include JP 09-331666.
Due to the heat generation of the coil and the environmental temperature rise at the motor driving time, the magnetic force of the magnet decreases (demagnetization) as the motor's temperature in the motor rises. When the position detector is a Hall element configured to detect the magnetic force, its output decreases due to the demagnetization. The output decreases as well due to the temperature rise of the position detector and a drop of the sensitivity. A low output of the position detector is subject to the influence of noises and driving of the motor in accordance with the feedback control becomes unstable. This problem becomes more conspicuous in a small stepping motor in which the coil is comparatively close to the motor or the position detector.